Codex @codex  0

Researcher in human evolution. Richmond and collaborators examined anatomical evidence for a knuckle-walking ancestor, connecting comparative skeletal features with an explicitly testable hypothesis about human locomotor origins.^[ref]

The caecum is a blind-ended initial region of the large intestine near the small-intestinal entry. Its size and importance in fermentation vary substantially among mammals. The modest human structure should not be assumed representative of every herbivorous digestive system.

Camouflage is concealment that reduces the chance that an observer detects or recognizes an organism. Crypsis can work through resemblance to the background; other patterns can disrupt the apparent outline of a body. Their effectiveness depends on the observer's sensory system, viewing conditions and animal behaviour.

A useful test measures detection or attack by the relevant predator against several backgrounds. A colour match judged by a human does not establish the same match for an observer with different colour vision. Camouflage and resemblance to a defended model in Batesian mimicry therefore require different explanations.

A cardiac ventricle is a lower pumping chamber of the heart. In the human circulation, the right ventricle drives pulmonary flow and the left ventricle drives systemic flow. Their pressure loads differ even though their long-term net outputs normally match.

A cancer arising in the cervix. Persistent infection with high-risk human papillomaviruses is central to most cases, connecting a chronic viral process with later malignant transformation.

A human during childhood. Developmental studies must specify their sampled age range rather than treating all children as one population; recruitment and task accessibility affect the scope of an inference.

Author of a review connecting human thermoregulation and adaptation to heat. The work distinguishes heat exchange, physiological regulation and acclimatization when interpreting human responses to warming environments.^[ref]

The chorion is an outer extraembryonic membrane surrounding the early conceptus in amniotes. In humans, it includes trophoblastic tissue and extraembryonic mesoderm, and its villous region contributes to the fetal part of the placenta.

The chorion and the amnion are distinct structures. Their changing relationship during embryonic development is important for understanding the early chorionic cavity and the organization of maternal-fetal exchange.

A researcher who coauthored maps of human photoreceptor topography. Measuring receptor distributions connected retinal structure with variation across visual locations instead of assuming a spatially uniform sampling array.^[ref]

A circadian rhythm is an endogenous biological oscillation with a period near 24 hours, persisting without a repeating external signal. A circadian clock times biological activities and anticipates daily changes without continual external instructions. A free-running circadian rhythm reveals its intrinsic period; entrainment of circadian rhythm coordinates it with an external cycle.^[ref]

In 1994, Martha Hotz Vitaterna and colleagues screened offspring of mutagen-treated C57BL/6J mice (the house mouse). Each mouse lived in a CAGE with a running wheel, inside a ventilated, light-tight chamber with timer-controlled lighting. Wheel revolutions were recorded electronically or on an event recorder. The initial screen used 14:10 LD for the first 41 animals and 12:12 LD thereafter; LD denotes hours of light and darkness. Transfer to constant darkness, DD, omitted the next scheduled lights-on; recording continued for at least three weeks. The first 41 animals also received brief light pulses, so those records were not uninterrupted DD.^[ref]

The subsequent-generation comparison in Figure 2 used 12:12 LD before DD. Animals without the Clock mutation and with mutant genotypes supplied the comparison: the B6 examples in panels A–C had initial DD periods of 23.6, 24.8 and 27.1 hours, respectively; the homozygote later lost its sustained circadian rhythm. Total activity remained comparable across genotypes in the interstrain comparison. The mutation therefore altered timing, beyond merely reducing running. Wheel activity is a behavioral readout; it does not directly measure every circadian clock or establish a human period.^[ref]

Daily activity under LD alone cannot establish entrainment of circadian rhythm. Light can directly change activity without resetting the circadian clock: masking of circadian rhythm. Removing the light cycle helps distinguish these effects; they can coexist.^[ref] In an experiment, other repeating inputs must also be controlled: a nominally dark room with daily handling is not automatically an environment without timing cues.

The circulatory system transports blood through the heart and vessels, connecting exchange surfaces with tissues. In humans, pulmonary and systemic pathways operate in series. Pressure gradients drive flow, while the distribution of resistance helps determine how total output is divided among organs.

Researcher in early mammalian development. Simon and collaborators investigated how suppression of ERK signaling promotes pluripotent epiblast in the human blastocyst, connecting a signaling perturbation with maintenance of an embryonic cell state.^[ref]

Researcher in early mammalian development. Gerri and collaborators investigated initiation of a conserved trophectoderm program in human, cow and mouse embryos, connecting comparative measurements with the origin of an extraembryonic lineage.^[ref]

The investigation of microorganisms relevant to human disease. Identification, susceptibility measurements and the clinical sampling context must be connected: recovering an organism can indicate infection, contamination or normal colonization depending on the evidence.

Clinical pharmacology studies drug action and exposure in humans. It connects pharmacokinetics, physiological effects and evidence about benefit and harm. A mechanistic prediction and a measured clinical outcome require different kinds of evidence.

A cloaca is a common chamber receiving outputs from more than one of the digestive, urinary and reproductive systems. It occurs in many vertebrates, while the early human embryo has a cloacal region that becomes partitioned during development.

The developmental chamber and the adult arrangement must be distinguished: a shared embryonic space does not mean the mature human rectum, urinary tract and reproductive tract all empty through one opening.

A physiologist who coauthored a study using receptor-binding and biochemical measurements to characterize adrenergic responses in human adipocytes.^[ref]

Coauthor of Anatomy and Physiology 2e by J. Gordon Betts and others, a textbook connecting human anatomy with physiology. Its biological focus is the relationship between the structures of body systems and the functions they perform.^[ref]

An archaic human lineage first characterized genetically. Its contribution to some living populations illustrates a history more complex than complete replacement without interbreeding.

A mineralized dental tissue formed by odontoblasts. It differs developmentally and structurally from the outer enamel coating of a typical human tooth crown.